The dudes at the local shop are telling me I run way too rich at 12.8 for most of my dyno runs. A lot of the dynos I see on the site are in that range. Can anyone comment on whether or not that is an acceptable ratio?

I do live in Colorado so I have no idea if that makes a difference or not.

 

are you running a comptech supercharger?

 

lol, no, stock and / or header

 

12.8 to 13.0 in open loop mode is pretty ideal for a naturally aspirated setup. I think most NA people aim for that range. I guess you could go a little leaner, but that's when it gets more dangerous and the risk probably isn't worth the reward.

 

I run about a 14.7 and I have Injen CAI, Comptech Header, Random Technology High-Flow Cat, and Hondata ECU Reflash.

Is this a normal air/fuel ratio for this kind of setup?

 

Yeah this is perfectly normal. When you are not on the gas hard, and when you're at idle, you should get a perfect 14.7 from the ECU. This is what is called closed loop mode for the ECU. This mode is met for efficiency and when you're just cruising.

When you get on the gas more then you should see the a/f ratio change to a lower value, usually between 12.0 and 13.0. (For a NA setup). This is a sign that the ECU had switched over to closed loop mode. In closed loop mode the ECU is more agressive and stops worrying about efficiency, making performance a higher priority.

 

Thanks Kenny for the quick response

...so does that mean when it goes to a lower number (ratio), does that mean the car is running leaner or richer?

 

Yeah no problem man

Lower means more rich. Higher means more lean.
14.7 is the ratio where the mixture of air and fuel is perfect.

I'm guessing you're probably asking because you're monitoring the a/f ratio with the Brockway R920. Just make sure when you go WOT that the air fuel ratio is going below 14.7. That shows that the ECU is now in open loop mode. Then pay attention to your a/f numbers when you're at full throttle.